Is 347 stainless steel similar to 321 stainless steel?

Is 347 stainless steel similar to 321 stainless steel?

347 stainless steel is similar to 321 stainless steel in that it is often used as a stable replacement for Type 304. However, in the case of 347, the stabilizer is columbium. This metal enhances 347's already existing ability to withstand intergranular corrosion for maximum performance. Additionally, columbium allows 347 to be heated repeatedly at temperatures up to 1650° F. As a result, the metal is often used in high-temperature equipment such as gaskets and expansion joints, as well as in rocket engines and chemical manufacturing.

In addition to its heat resistance, 347 has better resistance to creep and stress crack corrosion. This is another advantage of the Type 304, as the characteristics of the 347 may be better suited to environments where stability is a primary concern.

Type 347 is known for its suitability for all common welding techniques as well as hot and cold working. However, when heat treating, the metal must be heated to a range of 2100 to 2250°F. This is due to the fact that 347 cannot be work hardened under heat treatment. Cold reduction is the only method that can exploit the alloy's high properties.

Stainless Steel 347H is another stainless steel in the class of metals labeled precipitation hardened steels. It has many of the same features and properties as stainless steel 347. In addition to its higher carbon content, the alloy is stabilized by the addition of niobium or sometimes tantalum. Both of these properties allow 347H to be exposed to temperatures higher than what 347 and 304 stainless steel grades can withstand. 347H has high corrosion resistance and is therefore commonly used in high stress, high corrosion environments where exposure is often severe. High temperature manufacturing, steam piping, boiler tubes, chemical processes and steam services all benefit from the resiliency of 347H. This elasticity, in turn, is due to the potentially elevated chromium content in the 347H composition.

The metal exhibits high workability with the most common welding techniques. Can be heat treated but will not react. Only cold working is enough to increase the toughness and strength of 347H.

Specifications

Physical Properties

Chemical Composition